Earnings Per Share - Schedule of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		2 Months Ended	3 Months Ended								5 Months Ended		10 Months Ended	12 Months Ended
	May 31, 2018	May 31, 2018	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017		Mar. 31, 2019	Mar. 31, 2019		Mar. 31, 2018		Oct. 31, 2016
Earnings Per Share [Abstract]
Net income		$ 49	$ (19)	$ 38	$ 24	$ 29	$ 32	$ 104	$ 40	$ 32	$ 36		$ 23	$ 72		$ 208		$ 80
Common share information:
Weighted average common shares outstanding for basic EPS (in shares)	165,700										142,430			164,560		142,430		142,430
Dilutive effect of stock options and equity awards (in shares)											0			260		0		0
Weighted average common shares outstanding for diluted EPS (in shares)											142,430			164,820		142,430		142,430
Earnings per common share:
Basic (in dollars per share)			$ (0.12)	$ 0.23	$ 0.15	$ 0.18	$ 0.22	$ 0.73	$ 0.28	$ 0.22	$ 0.25	[1]		$ 0.44	[1]	$ 1.46	[1]	$ 0.56	[1]
Diluted (in dollars per share)			$ (0.12)	$ 0.23	$ 0.14	$ 0.17	$ 0.22	$ 0.73	$ 0.28	$ 0.22	$ 0.25	[1]		$ 0.44	[1]	$ 1.46	[1]	$ 0.56	[1]

[1] (1) Earnings per common share information for the fiscal year ended March 31, 2018, the five months ended March 31, 2017, and the fiscal year ended October 31, 2016 is computed using the 142.43 million shares of Perspecta common stock resulting from the Distribution as Perspecta did not operate as a stand-alone entity during the period, and therefore, no Perspecta common stock, stock options or other equity awards were outstanding and no dividends were declared or paid by Perspecta.